What's strange to me is that sometimes when I play back these live improvs, I hear a lot more mistakes than I remember actually making.
And it's quite possible that it's not in my head.
I already noticed that my digital piano treats really quiet notes differently than what ends up in my software.
For instance, on a real piano, if you press the key slowly enough no noise will be made at all. And my digital piano is the same way. As it should.
I don't know if it's Reason Pianos in general, or just the specific piano patch I default to, but slowly pressing the key will instead just result in a quiet piano note rather than no note at all.
So to sum up, what might be happening is that I'm slipping and playing the wrong note live but I hit it soft enough that it doesn't make a tone on my digital piano but when played back through the software, suddenly there are notes where there shouldn't be.
Something like that.